Well, I bought my 1998 Chevy Silverado Z71 4X4 in August of 2002, with about 118,000 miles on it. It was a construction truck prior to me purchasing it. Right now, it has a little over 285,000 miles on it. I've replaced a few parts on the truck more than once, such as the power steering pump I've replaced about 2-3 times a year.
The clear coat on the paint is peeling off, which I've noticed on many Silverados around the same year and body style.
The leather interior is in pretty nice shape, apart from a tear in the driver's seat along the seam; had to use duct tape to hold it together.
Replaced the ignition last year; the ignition wore out to the point that I could start the truck without the key in the ignition.
Have had a few problems with the A/C unit. It doesn't like to hold the freon in, and it leaks out, slowly, but does completely leak out. I've replaced a couple of gaskets and one of the lines to the A/C unit. It also has a tendency to blow cold air for a while, then go hot for a few minutes, then back to cold. The light on the A/C button goes on and off on its own.
I've also had a problem with a oxygen sensor on the truck. The engine service light turns on and off on its own, even when it was just worked on. I was told it's a sensor that is the problem. Doesn't bother me much, but is a little annoying that I get it reset, and then it comes back on a few weeks later.
The steering on the truck is very loose, it can be turned with one finger, even at about 30 mph. A friend of mine has a 1990 Silverado that is the same way. I don't know if that was the way it was from the factory when new.
The most recent problem with the truck was on 8/16/2011, when I noticed the truck was leaking a lot of fluid. I took it into the repair shop, and was told that the intake manifold is leaking and that it would be about $600.00 to repair, which I am not too pleased about.